diff --git a/compiler/cpp/src/thrift/generate/t_py_generator.cc b/compiler/cpp/src/thrift/generate/t_py_generator.cc
index 9c82b6c..f0a153c 100644
--- a/compiler/cpp/src/thrift/generate/t_py_generator.cc
+++ b/compiler/cpp/src/thrift/generate/t_py_generator.cc
@@ -1961,8 +1961,10 @@
       indent(f_service_) << "def write_results_success_" << tfunction->get_name()
                          << "(self, success, result, seqid, oprot):" << endl;
       indent_up();
-      f_service_ << indent() << "result.success = success" << endl
-                 << indent() << "oprot.writeMessageBegin(\"" << tfunction->get_name()
+      if (!tfunction->get_returntype()->is_void()) {
+        f_service_ << indent() << "result.success = success" << endl;
+      }
+      f_service_ << indent() << "oprot.writeMessageBegin(\"" << tfunction->get_name()
                  << "\", TMessageType.REPLY, seqid)" << endl
                  << indent() << "result.write(oprot)" << endl
                  << indent() << "oprot.writeMessageEnd()" << endl